Technical Field
The present invention relates to a cell culture bag and a cell culture method.
Description of the Related Art
In the related art, a stainless culture tank has been mainly used for expanded culture of cells. However, introduction of a plastic cell culture bag by which it is possible to reduce burden such as cleaning validation.
For example, a culture container of cells which is formed of plastic having gas permeability and in which the wall of the container is formed in a cylindrical shape, the cross-sectional surface is formed in any one of an angular cylindrical shape with a regular polygon shape, a spherical shape, and a hemispherical shape during culture is disclosed in JP2005-295904A.
It is considered that it is necessary to transplant 1×109 or more differentiated cells into a patient in order to treat, for example, hepatic disease or cardiac disease through cell transplantation. Therefore, development of mass culture technology of pluripotent stem cells is indispensable in order to realize the transplantation.
It is necessary to increase the volume of a cell culture bag in order to increase the scale of cell culture. However, when a cell suspension or a culture solution is stored in the cell culture bag by simply increasing the volume of the cell culture bag, the bottom portion of the cell culture bag is expanded and gas is insufficiently supplied to a center portion of the cell culture bag. In addition, in a case where a large amount of culture solution is stored, there is a problem of insufficient strength of the cell culture bag. A method for dividing a storage space of the cell culture bag into a plurality of regions is considered as a method for solving these problems. However, in this case, there is a concern that circulation of the cell suspension or the culture solution between the plurality of divided regions may be inhibited, and therefore, the environment of culturing cells between the plurality of divided regions may become inhomogeneous. As a result, there is a concern that the quality of cultured cells may become inhomogeneous despite the fact that the cells are cultured in the identical cell culture bag. According to a culture container disclosed in, for example, JP2005-295904A, the environment of culturing cells easily becomes inhomogeneous between a plurality of cylinders formed through heat sealing. In this manner, in the cell culture bag in the related art, it is difficult to culture a large amount of cells at the same lot as each other which are required for realizing treatment performed through cell transplantation and are guaranteed to have uniform quality.